Sudan Madhuri, Kheifets Leeka I, Arah Onyebuchi A, Divan Hozefa A, Olsen Jørn
Department of Epidemiology, UCLA School of Public Health, University of California, Los Angeles, California, USA.
1] Department of Epidemiology, UCLA School of Public Health, University of California, Los Angeles, California, USA [2] Department of Public Health, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
J Expo Sci Environ Epidemiol. 2014 Sep-Oct;24(5):482-8. doi: 10.1038/jes.2013.56. Epub 2013 Sep 25.
In this study, we demonstrate the complexities of performing a sibling analysis with a re-examination of associations between cell phone exposures and behavioral problems observed previously in the Danish National Birth Cohort. Children (52,680; including 5441 siblings) followed up to age 7 were included. We examined differences in exposures and behavioral problems between siblings and non-siblings and by birth order and birth year. We estimated associations between cell phone exposures and behavioral problems while accounting for the random family effect among siblings. The association of behavioral problems with both prenatal and postnatal exposure differed between siblings (odds ratio (OR): 1.07; 95% confidence interval (CI): 0.69-1.66) and non-siblings (OR: 1.54; 95% CI: 1.36-1.74) and within siblings by birth order; the association was strongest for first-born siblings (OR: 1.72; 95% CI: 0.86-3.42) and negative for later-born siblings (OR: 0.63; 95% CI: 0.31-1.25), which may be because of increases in cell phone use with later birth year. Sibling analysis can be a powerful tool for (partially) accounting for confounding by invariant unmeasured within-family factors, but it cannot account for uncontrolled confounding by varying family-level factors, such as those that vary with time and birth order.
在本研究中，我们通过重新审视丹麦国家出生队列中先前观察到的手机暴露与行为问题之间的关联，展示了进行同胞分析的复杂性。研究纳入了随访至7岁的儿童（52,680名；包括5441对兄弟姐妹）。我们考察了兄弟姐妹与非兄弟姐妹之间以及按出生顺序和出生年份划分的暴露情况和行为问题差异。在考虑兄弟姐妹间随机家庭效应的同时，我们估计了手机暴露与行为问题之间的关联。行为问题与产前和产后暴露的关联在兄弟姐妹（优势比（OR）：1.07；95%置信区间（CI）：0.69 - 1.66）和非兄弟姐妹（OR：1.54；95% CI：1.36 - 1.74）之间以及兄弟姐妹内部按出生顺序有所不同；这种关联在头胎兄弟姐妹中最强（OR：1.72；95% CI：0.86 - 3.42），而在晚出生的兄弟姐妹中为负（OR：0.63；95% CI：0.31 - 1.25），这可能是由于随着出生年份的增加手机使用量上升所致。同胞分析可以成为一种强大的工具，用于（部分）解释由家庭内部不变的未测量因素导致的混杂，但它无法解释由变化的家庭层面因素（如随时间和出生顺序变化的因素）导致的未控制混杂。
